I spent the last few days sick in bed in a Jakarta hotel room without any Internet. What little lucidity I had was spent on odd hacks. One of them was particularly neat or particularly nasty depending on your perspective.
It is a reader extension for list hoisting and splicing. You can write (a `b` c) and it will be read as (b a c). It is right recursive, so that (a `b` c `d` e) is read as (b a (d c e)). When the unhoisted segments are lists of length greater than one, they are wrapped in a singleton list rather than spliced. Thus (a b `c` d e) is read as (c (a b) (d e)). The splicing and hoisting tries to have a natural DWIM feel. While this lets you perform surgery on any lists in the reader, its strongest point is obviously infix function applications. Thus you can write x `+` y `+` z. The mechanics of hoisting and splicing is such that all infix operators are effectively right associative with uniform precedence. Thus x `*` y `+` z is read as (* x (+ y z)). Here is a quick demo transcript from the REPL: Clojure 1.2.0-master-SNAPSHOT user=> (defn dwim [x] (if (coll? x) (vec x) [x])) #'user/dwim user=> (defmacro => [bindings body] `(fn ~(dwim bindings) ~body)) #'user/=> user=> (defmacro where [body bindings] `(let ~(dwim bindings) ~body)) #'user/where user=> (defmacro || [body bindings] `(for ~(dwim bindings) ~body)) #'user/|| user=> (def add (x y `=>` x `+` y)) #'user/add user=> (add 3 5) 8 user=> (def curried-add (x `=>` y `=>` x `+` y)) #'user/curried-add user=> ((curried-add 3) 5) 8 user=> ((x `+` y `+` z) `where` x 3, y (x `+` 2), z (x `*` y)) 23 user=> ((x `+` y) `||` x (range 10), y (range 10), :when (even? x)) (0 1 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 10 11 4 5 6 7 8 9 10 11 12 13 6 7 8 9 10 11 12 13 14 15 8 9 10 11 12 13 14 15 16 17) user=> (0 `cons` 2 `cons` [1 2] `(map +)` [3 4]) (0 2 4 6) I gisted my diff, in case anyone wants to play around with this: http://gist.github.com/350244 I withhold judgement on its ultimate merits. :) -Per -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en To unsubscribe, reply using "remove me" as the subject.
